Datasheet ADN8810 clarification

I need to make a laser driver that can give current output from 0 mA to 250 mA. I checked ADN8810 datasheet and found the recommended circuit with 2 resistors (Rsn) which are having value written over them as 1.6V (instead of ohm/kohm). Is this a typo?

Also I need to ask whether the recommended circuit shown is to get 300mA only or the circuit connection stays the same for smaller current values as well?

  • Dear Rohan09,

    Firstly, sorry about the typo. The Rsn = 1.6ohm should be the correct ones in Fig. 1 of ADN8810 datasheet.

    We have noticed these typos and is working on the datasheet revision to fix these typos.

    Secondly, with the same Fig. 1 circuit configuration, the full scale current could be determined by the equation (1). In the equation two factors: Rsn & Vref would result in the expected full scale current. For example, if you have a Vref = 2.048V, Rsn = 3.7ohm, the resulted full scale current would be about 55.4mA. This leads to LSB (resolution) --> 55.4/4096 = 13.5uA. Or Vref = 4.096V, Rsn = 7.4ohm, you would get the similar full scale current 55.4mA.

    In general, we recommend a 4.096V as the Vref input.

    In case you have any further proprietary questions about ADN8810 application, please feel free to send your questions

    to or continue our open discussion here in EZ.

    Best Regards,


  • Thanks Dongfeng for the help,

    I have made the circuit as was in the datasheet and trying to get the output current, but failed. I am adding the circuit connection pdf file.Kindly have a look and let me know if somthing is wrong

    Baud rate =9600

    Bit resolution = 12 bit

    Master : TMS320F28377D

    Slave : ADN8810

  • Dear Rohan,


    ADN8810 is target to work with a laser diode, with about a threshold voltage: 1.6 ~ 1.8V. Please refer to datasheet Fig.1.


    In your prototype design, you have used one 1kohm resistor to replace the laser diode. At about Iout = 30uA,

    You could only generate 30mV, plus the voltage drop on Rsn, the resulted Vout voltage is still far below from the min. required Vcomp: 2.0V.  This might be the root cause why you failed to make ADN8810 works.


    Please replace the 1kohm resistor with one diode load (with a proper threshold voltage) hooked up as Fig.1 recommended, you would see a working ADN8810.


    Best Regards,



  • Hello Dongfeng:

    I tried using your email but it seems it doesn't work so I'll message you here.

    Based from your reply, you mentioned Iout = 30uA. Obviously this wouldn't fulfill the required Vcomp of 2V. But if Rohan chooses, Iout = 2mA, it should fulfill the minimum Vcomp of 2V. Will his circuit now work? I interpret this failure-or-not-failure situation as dependent on how much Iout you program ADN8810 to output.

    Anyway another question. If I will not use SB and RESET, do I just NIC them? connect them to ground? PVDD?